 body,
 html {
     height: 100%;
 }
 
 .wrapper {
     display: flex;
     flex-direction: column;
     min-height: 100%;
 }
 
 .nav-flex {
     flex: 0 1 auto;
     margin-bottom: 0;
 }
 
 .content {
     flex: 1 1 auto;
     position: relative;
     padding-top: 10px;
 }
 /* for index*/
 
 .index-screen {
     display: flex;
     flex: 1 1 auto;
     color: #767777;
     background-image: url('/images/slide01.jpg');
     background-position: center;
     background-size: cover;
     background-repeat: no-repeat;
     position: absolute;
     bottom: 0;
     top: 0;
     left: 0;
     right: 0;
 }
 
 .index-screen .title {
     font-size: 6vh;
     margin-top: 10vh;
     font-weight: 500;
 }
 /* for login */
 
 span.title {
     font-size: 12px;
 }
 
 .changeGroup {
     display: none;
 }